For filling insulating glass panes with a gas (filler gas) different from air, such as sulphur hexafluoride or a noble gas, particularly argon, it has been suggested to provide access to the interior of an insulating glass pane by maintaining, during the assembly of the insulating glass pane, the second glass sheet over a portion of its periphery at a distance from the spacer frame attached to the first glass sheet (Austrian Patent 368,985). In this operating technique, the filler gas is introduced into the interior of the insulating glass pane through the gap-shaped interspace formed between the second glass sheet arranged at a spacing from the spacer frame and the spacer frame attached to the other, first glass sheet.
The device known from Austrian Patent 368,985 has the drawback that it is not only necessary to flood the interior of the insulating glass pane with filler gas but also to flood the space between the two plates of the device wherein the process is carried out with a filler gas so that considerable amounts of gas are needed and not inconsiderable gas losses can occur.